raceway

I have a 2008 C300 7AT, 60k miles. I recently found some high frequency clicking/ticking noise coming from the engine compartment when I accelerate a bit hard, especially at lower RPM (say <2k), but sometimes happens at >3k RPM too. The noise will be gone in 1-2 seconds, but often comes back when I step on gas hard again. I cannot duplicate it at idle by revving the engine. I have been always using premium gas.

Does anyone have similar issue?

raceway

Anyone? I also found that at hard acceleration, the noises comes up during the rpm dropping when the transmission upshifts.

BenzTWM

Is it cold out when this is happening? More specifically... are you heating your car while this is happening? I have a similar noise in my car that I am 100% sure is the blower fan to my heating unit, only occurs when I am heating my car and during acceleration... something with the utility belt more than likely?

raceway

no, it is there even i turned the fan off. i am suspecting the belt, but it does not make sense since i cannot create the noise when it is idle.

dl94lopez

Got something similar like you Raceway, constant annoying flaps noise at accelerating and decelerating. No noise when cold though, start flapping up when worming up. Can be from the gear box? Any help really appreciate.

snowmuch

Im getting the same noise but only when I brake mostly at high speed sometimes at low speed braking.

IncognitoSphinx

I know the original poster posted this question a while back but i used to have the same problem in my 2009 C300. I found that when I ran regular gas, the car would make a ticking sound when I accelerated hard. When I started using premium gas, the ticking completely went away. Occasionally, my wife will forget and fill it up with regular gas. When that happens the ticking sound come right back.

mercedes4ever

Pinging or detonation, refer vid....

Glyn M Ruck

Knock, pinging, preignition, detonation by whatever name you know it. Should not happen with high octane fuel. Can be destructive.

When next at the dealer ask them to check that your ECU is set on a more forgiving map. So that it can adequately retard the timing when the knock sensor detects the onset of knock.

Only possible with a Star.

Cesarek94

Did you guys ever figure out what was causing it

Butterback

Exactly my issue with a 2015 C300.... When i accelerate hard, I hear a click/ticking sound right before it speeds up.

SLOBENZ

did you ever figure out what it was !?! I have the same problem! I have no cel !!!! It makes me lose acceleration after the clicking sound !!!!! The dealer couldn’t find the problem and I got charged for no reason 😡

Victorc300

Is that the noise? Mine is going in next Thursday! Anyone knows what it is?

DIBAJ

Same problem here! I've had an other engine problem, got it rebuilt, sound went away but started hearing it again about a week ago. Anyone figured it out? I almost want to sell the car because of its mechanical problems.

Victorc300

Sold the car, they re-built the engine same noise was still present I deducted that it has to come from the torque converter, I had them replace it and no more noises after that. Hope that helps.

riveraera$

Was it the utility belt I can’t replicate the noise when I put it in neutral and rev